


Long, Lanky Experiments

by TellTaleKael



Series: Error’s Dolls [3]
Category: Undertale (Video Game)
Genre: Anal Sex, Blue Fucks Stretch Without Stretch Knowing, Blue Is Nasty It Turns Out, Blue/Stretch - Freeform, Come Eating, Drunk Sex, Error Is Nasty, Error Might Be Pining?, Error Sans/Underswap Papyrus, ErrorHoney, Error’s Shitty Morals, Forced Sex, Hate Sex, In chapter 2, Incest, Kinda?, M/M, Masturbation, Or not, Public Sex, Rimming, Sex Doll Magic, Swapcest - Freeform, Underswap Papyrus/Underswap Sans (Undertale), Voyeurism, Who Knows?, implied alcoholism, nonconsensual incest, please mind the tags, unknowing incest, ”Hey I’m Not As Bad As I Could Be”
Language: English
Status: Completed
Published: 2021-02-17
Updated: 2021-02-17
Packaged: 2021-03-12 20:46:55
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 2
Words: 2,037
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29515530
Author URL: https://archiveofourown.org/users/TellTaleKael/pseuds/TellTaleKael
Summary: Please note the tags, this contains non-con! Don’t read if you can’t handle that please!
Relationships: Papyrus/Sans (Undertale)
Series: Error’s Dolls [3]
Series URL: https://archiveofourown.org/series/2146278
Comments: 20
Kudos: 95





	1. Chapter 1

**Author's Note:**

> Please note the tags, this contains non-con! Don’t read if you can’t handle that please!

Error wanted it known that he didn’t only use the dolls for his own sexual gratification. His favorite was his Horror doll. Any time the broken skeleton began to hurt, Error could take the doll and rub the splotch on the skull that stood in for his broken scar, lulling Horror to relax. Every so often, he stuffed (stolen) food inside the doll, to combat the constant hunger he knew the other felt. It meant that Horror had less episodes than usual, which was good for him and everyone around him. 

He’d made a Blue doll too. As much as he wanted to fuck it, so see Blue all stretched out and flushed, he couldn’t bring himself to do it. He hugged it instead, whenever he wanted an embrace that his body wouldn’t allow him to have. It never failed to make the real Blue smile, albeit in a confused manner. He had no clue where the soft, warm feelings came from, but he seemed to like them. 

Error was looking at the Blue doll, one day. His magic itched, seeking release. He’d been careful to not do anything untoward with any of Nightmare’s crew for a while, just in case. Not that Nightmare seemed very interested in finding out who had taken control over him. No, he and Cross were too busy fucking on every available surface in the castle, like they meant to mark it all as theirs. It was about time, but also gross as hell to walk in on them. 

Feeling nervous, Error pressed a kiss to the doll’s mouth. He just couldn’t make himself do anything more, releasing it and watching the little Blue be lifted up by his strings. He opened a portal to look at the real Blue, who was talking with his Alphys.

“-at Muffet’s again, of course,” Blue said, browbones narrowed as he frowned. “He’s been spending more time there lately. Drinking again.” He sighed, crossing his arms.

Error opened a second portal, peering into the Muffet’s of Underswap. Sure enough, Stretch was at the bar, chin on the polished wood surface, hiccuping. It looked like he had finally been cut off, but was far too drunk to stand. Stupid beanpole. 

Error watched Stretch sway on his stool, when suddenly an idea hit him. He didn’t know why he hadn’t thought of it before. Opening his palm, a doll dropped into his hand. The orange sweater matched that of the skeleton sitting at the bar. He had no qualms about messing with Blue’s lanky brother. 

He’d not messed with any Papyruses before. Oh, he’d made dolls of them, of course, but it didn’t amuse him as much to do things to them as it did his fellow Sanses. Perhaps it was a form of self-deprecation? He wasn’t a psychologist, thank fuck; he knew one would probably have a field day with all of his issues. 

Gripping the doll, Error tickled his phalanges down the spine. Stretch shivered, but otherwise looked unaffected. He wouldn’t be for long. Bringing his hand up, he let his tongues snake out, one dipping below the hem of the shorts he had created for the small figure. Through the portal, Error watched Stretch drop his forehead onto the bar, hiding his rapidly heating face.

Strangely enough, Stretch was already formed below his shorts. Error curled his one tongue around Stretch’s cock, lapping at the head. He almost tasted sweet. A second tongue joined in, teasing against Stretch’s entrance. Back at the bar, Stretch shifted on the stool, unconsciously sticking his ass out, as if asking for more. Error obliged, working a tongue inside, wet and slick enough to prep the other.

As much as he hated Stretch, Error didn’t enjoy hurting partners, so he spent plenty of time slowly tonguing him open. It was so much sweeter when they couldn’t help but enjoy was he did. That meant he wasn’t as bad as he could be, right?

Once he figured Stretch was- heh- _stretched_ enough, Error brought the doll down. He freed himself from his shorts, rubbing the tip against Stretch’s entrance. Only when the other was a squirming mess did Error enter in one steady thrust. 

It was different than using a pussy. Not a slick, but tight for sure. Error started slowly, lifting the doll off of him, before carefully pushing it back down. At the bar, Stretch had to look up as Muffet approached. Probably making sure he hadn’t passed out. Error paused, and he could practically see the relief in the tilt of Stretch’s shoulders. When he opened his mouth to reply, Error gave a mighty thrust, grinning at the way Stretch grasped at the edge of the bar, clenching around Error tightly. Error closed his sockets for a moment, but when he opened them, Stretch had teleported out into the alley beside Muffet’s. He yanked his shorts down, fisting his cock desperately. Error began thrusting again, following the brutal pace Stretch set with his hand. 

Before he knew it, Stretch was clamping down around Error and spilling into the snow. Error followed with a strangled shout, hot magic filling Stretch, dark blue and swirling within the orange of his ecto. Error pulled out, patting Stretch on the skull before letting go. His strings took care of the doll while he wiped himself off with his soiled shorts, aftershocks of pleasure still racing up his spine, fighting off the pain of his glitches nicely. 

Maybe using a Papyrus wasn’t so bad after all. He wondered if Stretch would even remember the incident once he sobered up. Even if he did, who would believe him?


	2. Chapter 2

**Notes for the Chapter:**

> More non-con! Now including Blue, but the non-con isn’t towards Blue!

One of Error’s strings snapped, jerking him out of the mindless stupor he had been in. It was one that wasn’t still connected to him, but he could feel it all the same. A quick check told him it was the one he had given to Blue. Phones didn’t always work in the anti-void, so Error gave the scant few beings spread throughout the multiverse he could actually stand one of his strings, to call him in case they needed him. 

Opening a portal to Underswap, Error looked around. But before he could step through, Blue came barreling in. Error just barely managed to avoid running into the shorter skeleton, arm glitching where they had almost touched. “BluE? WhAt a-arE yoU dOinG?”

“How did you do it?” Blue asked, whirling around with his hands on his hips. Error closed the portal behind him, before anyone else came barging through.

“Do whAt-t?”

“Last time Stretch went on a bender, he came home with your magic in him. He didn’t go back until tonight! How did you do it?” Blue squinted at him. “I thought you couldn’t touch anyone without glitching out?”

It had probably been several weeks since Error had fucked the Stretch doll, if he had to guess. The asshole had gone that long without a drink? It was almost impressive. “I c-cAn’t,” he confirmed, shaking his head.

“Then how did you do it?”

Error shuffled, kicking one of his slippers against the floor of the anti-void. Blue tapped his foot.

“Error, please?” His hands fell from his hips, clenching into loose fists at his sides. “That’s the longest Papy has gone without drinking in... a long time.” 

“YoU woN’t LikE iT-T,” Error warned. Blue pinned him with a desperate look.

“Please?”

Error extended a hand, letting the Stretch doll fall into his grip. Brushing a thumb over the skull, he shrugged. 

“This?” Blue asked, stepping closer. Error nodded.

“It cOntAIns parT oF his-s coDE,” he explained. Blue looked confused. “WitH prOpEr inteNt... whAt yoU do to iT, happEns to hIm.”

“...Can you do it again?”

Error looked up, startled. “I j-jUst admiTteD to scRewinG your bRother wiTHout him knOwing,” he said after a moment. “YoU wanT me to dO it agAIn?”

Blue swallowed. “Yes. If it makes him stop drinking...” He licked his teeth. “Please, Error? You did it once already.”

Error stroked his phalanges over the doll. Doing what he had been alone was one thing. Could he do it with Blue right there? Knowing that Blue knew? He glanced at the hopeful expression on Blue’s face.

He could try at least.

Opening another portal, Stretch was right where he had been last time; swaying on a barstool at Muffet’s. He didn’t look quite as drunk as before, but he was definitely past tipsy. Error took a seat, cross legged on the floor of the anti-void. He let his tongues loll out from between his teeth, setting to work, worming their way beneath the khaki shorts. Through the portal, Stretch stiffened, a shiver running down his spine. He was already formed again, this time with both a cock and pussy. One of Error’s tongues curled around his cock, and the other teased the slit below it. 

Movement reminded him that Blue was still there. The shorter skeleton took a seat beside Error, watching his brother’s rapidly darkening face through the portal. A slight blush rose on Blue’s cheekbones.

“So, this is what you did last time?” 

Error hummed, making Stretch choke slightly. He waved off the concern of one of the other patrons, pulling his hood over his skull. Blue inhaled sharply.

There wasn’t as much prep needed this time, but Error lingered for a moment longer than necessary, taking in the sweet taste of Stretch’s magic. His own body had been summoned, tenting his shorts, magic itching for the pleasure it knew was coming.

He didn’t miss the telltale glow in Blue’s shorts, either.

Pulling his tongues back in his mouth, Error carefully worked the shorts aside. He shimmied his own down, but before he could slide inside, Blue spoke up.

“C-could I...?” His face was bright blue, eyelights shrinking slightly. Error licked his teeth, releasing his shorts. 

“OkAy... yOu havE to uSE intEnt,” he said, passing the doll over, careful not to let their hands touch. 

Blue held the doll, looking at it for a moment. He unbuckled his pants, rolling them down enough for a thick, short cock to spring free. Bringing the doll down, he prodded Stretch’s entrance lightly, hand trembling. He finally lined up right, sliding the doll down slowly.

“Oh stars... Papy,” he murmured, carefully gripping the doll and lifting it up. Error drug his eyes away, looking at the portal again. Stretch was clearly too far gone, standing up and stumbling out of the bar. He made it several buildings down before he collapsed in an alley. He clumsily tried to slide his hands in his shorts, unable to work the button, and ended up just rubbing himself through them, rocking in time with Blue’s thrusts.

Error instinctively changed his form, cock melting away and a pussy taking its place. He was wet enough for two phalanges to slide in easily, pumping them in time with Blue’s movements, visible out of the corner of his sockets. He wondered what that cock would feel like, short yet girthy. Blue was one of the most physically strong Sanses, and could probably hold Error down. He shuddered at the thought, glitching lightly, but the pain went well with the pleasure wracking his body. 

He clenched down around his phalanges and came when Stretch did. Blue followed not long after, pumping his magic into the drunk skeleton. Error pulled his hands out of his pants, idly rubbing the slick between his phalanges. 

Blue leaned forward, cock still buried in Stretch. He let his tongue flick out, just ever so slightly cleaning Error’s hand off of the thin magic.

By the time Error rebooted, Blue was dressed again, clothing impeccable, as if he hadn’t just fucked his brother through Error’s magic. The doll was neat and clean, redressed and tucked carefully on Error’s beanbag. “Thank you,” Blue said, nodding at the still-open portal. Stretch was gone, no doubt returned home by then. Error widened the portal so Blue could step through. Before he did, Blue looked back.

“Error... did you make a doll of me, too?”

“No,” Error lied. Disappointment flashed in Blue’s sockets.

“Oh. Okay.” He disappeared, the portal closing behind him.

Error could still feel Blue’s tongue on his phalanges. 


End file.
